What if I bought several gear sets for some of the servos I have, like the ones from Hitec that have a torque of 133 oz-in. Then instead of just using the whole gearset, use only the more prominent gears for most gear reduction over and over again on the servo's shafts for maximum torque.

To me it just seems like a matter of making sure the right gear is meshed with the last gear attatched to the potentiometer. As long as I do that, the servo should retain its 180 degree rotation, right?

As for RPM, servo speed isn't too much of an issue for me. I'd like the servo to move more slowly anyway.

I have 2 GWS servos that are close in specs. One is S03N and the other is S03T. The latter has double torque. The only difference between them is the motor size. The gear train is the same.

You can't change the gears unless they mesh with each other. I mean the combo gears have a small gear and a big gear in one piece. The small gear of the new combo has to be the same as the old one, and the big gear has to be matched with the small gear of the next combo so they mesh perfectly keeping the same distance between their axles. I.e. change a pair that has 12 and 24 with a pair that has 8 and 40 or something like that. You have to measure the pitch diameter of the gears (if I remember corectly) and keep the sum of the diameters the same.

This pack I intend to use to strengthen the wrist servo of my robot arm, which is a HS-645 MG. These are a servo gear set pack for just the individual gears I need to replace (or at least that's what it looks like judging from the photograph). This is exactly what I'm looking for since I can spend more money of the individual gear pieces I need (i.e. 8-40) instead of buying whole gear sets.

Yeah, I guess it's the plastic gear that may be damaged. Probably that's why they have sets with only this gear combo.

Here's how my servos got broken: My 1 year old doughter (now she's two years old...) was playing with the robot's arm while the arm was not powered and forced the servo slam the stop notch. One of the fine tooth gears lost one tooth because of the momentum. Of course, a new gear set will make it work as new, but I never got around to order it...

Here is an ideea to increase the strenght of the shoulder and elbow servos: use external gears or sprockets and chain (from ServoCity) to transfer the motion from the servo to a worm gear set. Take apart the servo and remove the pot and install 3 wires and mount the pot directly to the joint. This way the arm will retain the position without power and it will move at a nicer slower speed and with a lot more torque.

Yeah, I've already done the external gear method for the shoulder joint. Guess I might as well do it for the elbow and wrist servos as well. That sounds like it will definitely work, and it'll probably save me a lot of time in the long run.